This invention relates to vehicle dolly trailers adapted to haul large elongated loads. More particularly, this invention relates to a low profile dolly trailer for transporting elongated cylindrical loads at a level close to the ground.
Increasingly, massive structures must be moved from manufacturing sites to construction areas over state and federal highways. Because of road safety, state and federal authorities have adopted highway weight and length regulations which determine legal load limits for load carrying vehicles, the manner in which the load carrying vehicles may traverse a highway, and the weight distribution of load-carrying vehicles over the pavement. Loads exceeding the regulated weight or length limits often require special permits from state authorities. Although criteria for these permits may vary from state to state, the load-carrying vehicles must normally comply with a formula determined by the government authorities for safe travel across highways. Applying for and receiving these permits may delay transportation of the load which in turn negatively effects the construction project.
Dolly trailers are the vehicle of choice for transporting long heavy objects since they widely distribute the load over the roads. Examples of dolly trailers are described in U.S. Pat. Nos. 5,370,414, 4,762,192, and 3,438,652. Dolly trailers typically have a front assembly which supports the front portion of the load and a rear assembly which supports the rear portion of the load. The front and rear assemblies have an elevated frame. Bolsters are placed on the elevated ends to support the load. A drawback to these types of dolly trailers is that they elevate the load which gives it a high center of gravity so that the load has a tendency to wobble and turn over during the hauling operations. Another problem with this type of dolly trailer is that the raised load may not have the clearance to pass under some low lying obstacles such as bridges, thereby impeding the load's path and forcing the dolly trailer to detour around the obstacle.
Therefore, there is a need for a dolly trailer able to transport large cylindrical objects with reduced wobble and greater stability. Further, there is a need for a dolly trailer able to haul large cylindrical objects at a lever closer to the ground to permit the objects to pass under low lying obstacles.